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thetwood

Failed CO emissions - all controls removed - where to start?

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1 hour ago, thetwood said:

I can'd fine any numbers or markings on the injectors top or bottom...

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I've had the injectors out of my 1983 280ZX a few times, and those look like OEM injectors to me. They're weathered enough to show that they've been installed for a long time.

Edited by Pilgrim

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Those injectors aren't what I thought they were.  Nissan injectors all have the same number on the side, and use different colors to differentiate volume.  There should be a number/letter like A11000...  in this spot, below.  You have mystery injectors.  They could be 265 cc aftermarket turbo injectors instead of 188 cc NA injectors. That might explain the low fuel pressure and the reason he used an adjustable regulator.  Aftermarket injectors come in a variety of colors.

So, unfortunately, you might find that you are unable to raise fuel pressure to spec. without causing the engine to run really rich.  

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That is what I was thinking too. They are normally green in colour. I couldn't find anything on the colour, but they could be turbo injectors. That would make sense of the low fuel pressure.

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Does it make sense to change the injectors to oem? Or do I need to figure out what else was done to the engine first?

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If you find that your fuel pressure really is low and can't be raised then that would be an option.  Or you could have them flow-tested to see what you have.  It's just another unknown at this point.

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I was thinking that you might want to have them flow tested for two reasons. First, to determine what you have. Second, although it's running smoothly, it would be good to find out how well they are working.  

If they turn out to be turbo injectors, you should be able to find a buyer if you have the test results to show they're working well.  

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11 minutes ago, Pilgrim said:

I was thinking that you might want to have them flow tested for two reasons. First, to determine what you have. Second, although it's running smoothly, it would be good to find out how well they are working.  

If they turn out to be turbo injectors, you should be able to find a buyer if you have the test results to show they're working well.  

Suggestions on where to go to get them tested?

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15 minutes ago, thetwood said:

Suggestions on where to go to get them tested?

I've had this done once or twice, but it's not "rocket surgery" so there are many options you can find online. 

Mine were done in 2016 by Cruzin Performance, 1509 N. Orchard Drive, Traverse City, M 49686.  Phone: 213.796.5705.  (I keep a careful file, and found the receipt.)

I didn't request separate data on each injector, and don't recall if I got it.  The time previous to that, probably 15+ years ago, I used a gent in SOCAL and he labeled each injector separately.  You might request that detail.

Edited by Pilgrim

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OK. Here's my current plan after getting all of this advice:

1) I have a new fuel pressure gauge on the way. Confirm what the pressure really is.

2) I'm going to remove the fuel injectors and send them to be flow tested/cleaned. Figure out what I actually have.

3) I'm working on getting a charcoal canister and bracket. You were right, the new non-venting gas cap caused a vacuum in the gas tank without one.

Trying to decide how much else to change out. Should I switch back to a stock fuel rail while I already have the injectors out? that way I can add cold start back into the system?

May take me a while to get through this part, but I'm sure I'll have more questions once I get through some of this...

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My similar fuel rail has a T out the back. One side to the cold start, the other to an original equipment fuel pressure regulator from a '78. Worked out good for me. I can post up some pictures tomorrow if you want.

Cliff

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8 minutes ago, siteunseen said:

My similar fuel rail has a T out the back. One side to the cold start, the other to an original equipment fuel pressure regulator from a '78. Worked out good for me. I can post up some pictures tomorrow if you want.

Cliff

That would be great if you could. I don't mind continuing to get closer to stock, but it's going to take a lot of searching for parts, tracking things down and cost of course. If I can continue using things we already have that helps...

My first goal is to pass emissions. Doing so allows my son to drive to school and back and buys us time to make additional changes.

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Good move and reinstating the carbon canister, replacing the gauge and sending the injectors off for testing. You are eliminating some of the unknowns.

Once you get the injectors back or replace them, you can start sorting out you pressure regulator. Test run the pump and adjusg the FPR to 36psi. Then connect the vacuum line.

I don't think I would worry about the CSV or the AAR for now anyway. Mine starts easy in the summer and even in the early spring and late autum I can start it and play with the throttle for 30 seconds and then it idles on its own.

My experience with these old systems. If poeple start playing with the system, which is very clear in your case, they eventually focus their attention on the AFM. The temptation to play with the spring and ease of access is too much. See link for testing the AFM.

http://www.atlanticz.ca/zclub/techtips/afm/calibration/index.html

 

Plenty of other neat tips on Atlanticz. A good read while waiting for the injectors to come back.

http://www.atlanticz.ca/zclub/techtips/EFI&fuel.htm

The other thing I would reccomend is going through all the tests in the EFI bible.

 

Edited by EuroDat
Link to EFI bible

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I guess the fuel rail depends on how strict the visual inspection is? In some parts of the country they compare the engine to sample pictures to determine if components have been removed or tampered with. If a visual inspection isn't a big deal, Then the fuel rail can probably remain for now

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I doubt thr visual matters. Most just check emissions. For that matter, few people know what the original looks like.

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Haven't made a lot of progress yet. Still planning on pulling the injectors to have them flow tested, but haven't done so yet. It was my son's 16th birthday yesterday and he wants to drive his Z to the local Cars and Coffee this Saturday. We go a lot, but he's never gotten to take his own car. Seems like a worthwhile reason to wait a few extra days...

But I did receive a fuel gauge from Amazon yesterday. Put it in place of the Jegs inline fuel gauge and tested again. Got similar readings as before, and nowhere near 36. With the Begi fuel regulator hooked up, it sat at 10 psi. With not vacuum to it, fuel pressure was 16. 

Will send off the injectors this weekend and hopefully get some answers on that next week. But fuel pressure doesn't seem nearly what it should be.

IMG_3065[1].JPG

Edited by thetwood

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The pressure reading is actually great progress.  The numbers are the most important part of working with EFI.

You're at a point where you can calculate a cheapest path to where you want to be.  Find the atlanticz.ca page about calibrating your AFM and see if it has been messed with.  It might be most cost-effective for you to just buy the right injectors and calibrate your AFM.  If you send your injectors out and they're high flow rate you'll need to buy new ones anyway.

It's a learn-o-rama with the old EFI systems.  Have fun.

I found the page.  It's worth a read.

http://www.atlanticz.ca/zclub/techtips/afm/index.html

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Have been reading through the AFM documentation, then went to the car. The AFM is not original. It's from JEGS. I can't find anything on their site with the model number on it (A31-625 000), but it seems to be listed for an L28 and there's some faded marker on the body that looks like it says 280ZX.

The cover was sealed, but popped with a bit of a pry from a screwdriver. Inside, it doesn't look exactly like what's in the documentation but is close enough to work on. Glue blob is intact and I can't see where it's been adjusted. I'll go through it in much more detail, but just doing the quick fingering check, moving more than about a tooth in either direction did bad things to idle. I'll dig into the tests and go through the other suggested checks from the document when I get more time.

IMG_3067[1].JPG

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That AFM has been messed with in the past. Don't know if it's been adjusted, but that cover was definitely removed and reinstalled in the past. The glue's wrong.

That said... Other than trying to verify that it's the correct AFM for the system, don't spend any time worrying about adjusting it right now. That would be one of the last things to mess with. Get the fuel pressure correct and tracking intake manifold vacuum first, Fix the PCV routing so you aren't pulling huge amounts of unmetered air. Get the AFM mounted properly so gravity has the correct effect. Search out and fix any other vacuum leaks in the system.

Do all that first and go from there.

BTW - I recently stripped down an 82 motor and it has the same fuel rail and regulator system as the stock 78. If you just can't seem to get the aftermarket stuff working, we can work out some sort of trade for your aftermarket stuff. I know it's a "downgrade", but it comes with the advantage of being a known entity.

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If the glue blobs were intact after you removed the cover then leave it where it was with the intact glue blobs.  Never adjust it.

The procedure I linked to is for getting it back to where it is supposed to be.  The AFM should never be adjusted from its factory position.  There are better ways to tune the air-fuel ratio.

Edited by Zed Head

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11 hours ago, thetwood said:

Have been reading through the AFM documentation, then went to the car. The AFM is not original. It's from JEGS. I can't find anything on their site with the model number on it (A31-625 000), but it seems to be listed for an L28 and there's some faded marker on the body that looks like it says 280ZX.

The cover was sealed, but popped with a bit of a pry from a screwdriver. Inside, it doesn't look exactly like what's in the documentation but is close enough to work on. Glue blob is intact and I can't see where it's been adjusted. I'll go through it in much more detail, but just doing the quick fingering check, moving more than about a tooth in either direction did bad things to idle. I'll dig into the tests and go through the other suggested checks from the document when I get more time.

IMG_3067[1].JPG

It's a standard looking 280Z pre August 1977 AFM. Definitely not 280ZX. You can tell by the contact switch for the fuel pump. I have one with the same part number.

They produced a lot of part numbers for the hole sries, but essentually you have two types for the non turbo model. With and without switch.

Like I mentioned before. I would check the calibration by following the steps on Atlanticz, but only adjust it if you get a realy wonky reading.

1IMG_0110 (8).JPG

AFM-2.jpg

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I used an online calculator just for fun and it comes up surprisingly close to "turbo" injector for your measured pressure.  Assuming that the 188 cc number is at 36 psi. Some flow rate charts aren't clear on what pressure they measure at.  

Whatever you do, keep track of your starting points so you can reset them if needed.

http://www.atlanticz.ca/zclub/techtips/injectors/index.html

https://www.rcfuelinjection.com/technical

image.png

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Another thought, and a reason to just go  through the whole series of EFI component tests and measurements.  If your coolant temperature sensor circuit is "open" the ECU will dump loads of extra fuel thinking that it's super cold out.  It might be that that is the reason the PO lowered the fuel pressure.

You already have many of the important numbers.  Keep measuring and confirming.  A multimeter is a very valuable tool for the EFI systems.

You might save yourself some time and money by doing the full set of tests first.

Edited by Zed Head
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Going to leave the AFM alone for now. Planning on going through the fuel injection system and testing everything we can, testing vacuum, etc.

Did fine out a few more pieces of info. Haven't verified, but PO says the injectors should be original type, not turbo (we'll see). He did change out the throttle body, as many had observed. He also switched the cam to a Schnieder Racing Cam. I'm not sure exactly what that does or will mean, but one more piece of the puzzle.

My son turned 16 two days ago, so he wanted to get up early and go to Cars and Coffee. Gratuitous pic of him (the one with long hair) next to his car. He had a blast and we had a lot of people stopping to talk. Everyone had one or knew someone who did and have fond memories. Was fun.

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The factory system probably won't like the schneider cam. Schneider offers a lot of different cams. You will need to try to pin that down further

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